How to create a Striped Mirror logical volume

[RSA]

Hello.
I'm trying to create a striped and mirrored logical volume. I already installed PHCO_36746 with dependencies, this patch should enable HP-UX 11.23 for doing this.

http://www12.itrc.hp.com/service/cki/patchDocDisplay.do?patchId=pdb_na-PHCO_36746-1

But I'm still getting this error:

lvcreate -l 2 -i 2 -I 64 -m 1 /dev/vg02

Not allowed to create a striped and mirrored logical volume.
Install the "16TB LV and Striped Mirror feature enabling patch", to enable this feature.

It would be very nice if someone can help on this.

Thanks
Ralph

[Steven E. Protter]

Shalom Ralph,

LVM doesn't really do what you want it to do.

You can fake it out and achieve the same effect by doing the following:
1) lvcreate
2) Writing a script to do a rotating lvextend among the various disks. Charles Keenan has a good example in his book HP-UX CSE.

SEP

[James R. Ferguson]

Hi Ralph:

Did you install both PHCO_36744 and PHKL_36745 too?

Regards!

...JRF...

[Steven E. Protter]

Shalom Ralph,

LVM doesn't really do what you want it to do.

You can fake it out and achieve the same effect by doing the following:
1) lvcreate
2) Writing a script to do a rotating lvextend among the various disks. Charles Keenan has a good example in his book HP-UX CSE.

You may also be missing mirror/ux which is probably required to pull this off. mirror-ux is a pay for add in product.

SEP

[RSA]

Hi James,

yes, I already double checked. I have installed these two also.

Thanks
Ralph

[RSA]

Hi Steven,

MirrorUx is also installed on this system. I will have a look into the CSE book on Monday.
But I think or hope it's possible to get a striped/mirrored lvol with the specific patch.

Thanks
Ralph

[Sandman!]

Make sure that the patch installed correctly. Look in /var/adm/sw/swagent.log file for any errors related to that patch installation. How many PVs are part of vg02? It might be failing because you have only one PV as part of that VG.

~hope it helps

[Geoff Wild]

I didn't think you can do this - I thought all you can do is create "EXTENT-BASED MIRRORED STRIPES"

The other question is - if you have the need for both mirroing and striping - then why do both logically?

IE - why not do hardware mirroing instead?

Rgds...Geoff

[Sandman!]

>I didn't think you can do this - I thought all you can do is create "EXTENT-BASED MIRRORED STRIPES"

I concur with Geoff but apparently PHCO_36746 makes it happen. The patch database does not have enough information on how it is done. At the very least it should take a minimum of 4 PVs to create a striped and mirrored lvol. But that's just my 2 cents.

I am very interested in how that patch enables that functionality. Moreover it is better to have hardware based striping and mirroring (which is provided by most of the high end arrays like the XP storage line).

[Bernhard Mueller]

Ralph

Sandman said you would need at least 4 PVs for your command to work. However, reading the lvcreate manpage after installing the patches reveals that your vg would need at least 5 (!) PVs to to that.

I am currently looking for 5 disks, will let you know....

Regards,
Bernhard